@ajroach42 not really sending information over wifi (backscattering, producing radio signal that doesn't really have anything to do with wifi), but yeah, magic.I'm curious how well it works, and what is involved on the receiver end (haven't read the paper yet)

At some point, the difference between a "wifi receiver" and "RF receivers, including wifi" is splitting hairs, yeah?

Like, I understand that wifi is a specific protocol that uses a spectrum shared by lots of other devices, and that without the ability to generate more complex signals it won't actually be "wifi" but if a standard wifi radio can receive these signals and be made to understand them, wants the point of the pedantry?

@ajroach42@kurtm the thing is, it will only fall in the same range of frequencies as WiFi, but the modulation has nothing in common and it will completely ignore the protocol. So it's far from obvious how WiFi receivers could handle it.

@ajroach42@Thib There is no comma. It looks like they are talking about boxes that collect signals from these things and pass that on to Wifi. Like a bridge.

If I get a box talking RS232 to a host with wifi, I can claim it talks to "signal receivers including wifi". It's not speaking wifi. The host is speaking wifi. Using that specific awkward wording was a big tell to me.

I mean, it's very cool stuff, but it's not things without electronics speaking wifi.

@kurtm@Thib In the situation you're describing, there is a receiver other than the smartphone sitting between the device producing the signal and the wifi receiver that would receive and interpret the signal, and send the results out over wifi.

At some point, I'll actually read the paper and verify.

The neat thing here is that they are generating the signal without electronic components or electricity.

The details are covered in section 3.2 of the paper, which is linked from the page.

Basically, it uses a wifi transmitter and a wifi receiver. The transmitter is unmodified. The receiver is connected to a computer that is analyzing the data from the wifi receiver to look for the modulated signal from the 3d printed sensor.

Basically, they are using standard wifi hardware, with custom software on the receiving end.

@bastlynn the neat parts here are 1) this was done with readily available 3D printable material. 2) the circuits they print don’t require a power source beyond ambient WiFi signals, because they’re basically antenna. 3) the receiver doesn’t require any special hardware. Just WiFi and some custom software.

These things are neat! With some refinement they could be practically revolutionary.